Kornfeld and Bach, U.S. Pat. No. 4,198,415 claim trans-(.+-.)-5-permissibly substituted-4,4a,5,6,7,8,8a,9-octahydro-1H-pyrazolo[3,4-g]quinolines and their tautomers, the corresponding 2H derivative (I and II below) useful as dopamine D-2 agonists. ##STR1## wherein R is C.sub.1-3 straight-chain alkyl (methyl, ethyl, n-propyl) or allyl.
Each tautomer consists of two enantiomers, the 4aR,8aR and 4aS,8aS derivatives. These four enantiomers are pictured below--Ia and Ib for the 1H tautomers; IIa and IIb for the 2H tautomers. ##STR2##
The copending application of Titus and Kornfeld Ser. No. 439,238 filed 11/3/82 discloses a method of separating the tautomer pair I and II into their respective enantiomers (Ia and Ib or IIa or IIb) where R is n-propyl. Alternatively, the same enantiomers are prepared by using an optically-active intermediate. The copending application of Schaus and Booher, Ser. No. 639,107, also filed 11/3/82, separates the trans-(.+-.)-1-alkyl(specifically n-propyl)-6-oxodecahydroquinoline into its enantiomers, 4aR,8aR-1-n-propyl-6-oxodecahydroquinoline (III) and its 4aS,8aS-1-n-propyl-6-oxodecahydroquinoline (IV). ##STR3##
Reaction of III with the dimethyl acetal of dimethylformamide or tris dimethylaminomethane forms a 7-dimethylaminomethylene derivative, reaction of which with NH.sub.2 NH.sub.2 yields the tautomeric enantiomer, Ia.revreaction.IIa.
The tautomeric pair Ia.revreaction.IIa has been found to be useful in treating both hypertension and sexual dysfunction in mammals, see Hahn et al, J.P.E.T., 224, 206 (1982) and the copending application of Foreman, Ser. No. 518,906 filed 8/1/83.
The metabolism of the enantiomeric tautomers, Ia.revreaction.IIa, in mammals has not hitherto been disclosed nor have ring-oxygenated derivatives of trans-(.+-.)-5-permissibly-substituted-4,4a,5,6,7,8,8a,9-octahydro-1H(and 2H)-pyrazolo[3,4-g]quinolines.